Hi, the testcase expose a bug in nothrow propagation. We forget to set the flag that call from thunk may throw. I probably should flip the default of the flag to prevent similar bugs next stage1.
Bootstrapped/regtested x86_64-linux. Comitted. Honza PR ipa/68184 * g++.dg/torture/pr68184.C: New testcase. * cgraphunit.c (cgraph_node::analyze): Set can_throw_external. Index: testsuite/g++.dg/torture/pr68184.C =================================================================== --- testsuite/g++.dg/torture/pr68184.C (revision 0) +++ testsuite/g++.dg/torture/pr68184.C (revision 0) @@ -0,0 +1,31 @@ +// { dg-do run } +namespace { +struct IFoo { virtual void foo() = 0; }; +struct IBar { virtual void bar() = 0; }; + +struct FooBar : private IBar, private IFoo +{ + void call_foo() + { + try + { + static_cast<IFoo*>(this)->foo(); + } + catch( ... ) {} + } + void foo() { throw 1; } + void bar() {} +}; + +void test() +{ + FooBar foobar; + foobar.call_foo(); +} +} +int main() +{ + test(); + return 0; +} + Index: cgraphunit.c =================================================================== --- cgraphunit.c (revision 231122) +++ cgraphunit.c (working copy) @@ -575,6 +575,7 @@ cgraph_node::analyze (void) cgraph_node *t = cgraph_node::get (thunk.alias); create_edge (t, NULL, 0, CGRAPH_FREQ_BASE); + callees->can_throw_external = !TREE_NOTHROW (t->decl); /* Target code in expand_thunk may need the thunk's target to be analyzed, so recurse here. */ if (!t->analyzed)